Ultrasonic swivel insert

ABSTRACT

An ultrasonic insert carries a rotary bearing adjacent to the transducer. The bearing slidably engages an ultrasonic handpiece. When seated in the handpiece, the insert is substantially decoupled, on a rotary axis, from the handpiece. A rotary force need only be applied to the insert to rotate it in the handpiece. Alternately, an adaptor can be inserted into the handpiece. The adaptor slidably receives a conventional ultrasonic insert. The conventional insert can be easily rotated with a force applied only thereto, relative to the handpiece.

[0001] This is a Utility Application claiming the benefit of the earlierfiling date of Provisional Application Ser. No. 60/223,447, filed Aug.4, 2000 and Ser. No. 60/270,687, filed Feb. 22, 2001.

FIELD OF THE INVENTION

[0002] The invention pertains to ultrasonic inserts of a type used inmedical/dental treatments. More particularly, the invention pertains tosuch inserts with enhanced operating efficiency and user comfort.

BACKGROUND OF THE INVENTION

[0003] Ultrasonic scalers are used in dental offices for de-plaqueingteeth. Unlike manual scalers, these instruments are powered i.e., thetip of the instrument vibrates at an ultrasonic frequency allowing quickand easy debridement. The operator has less hand fatigue as most of theenergy for removing the plaque comes from the generator that powers theinstrument. The dental practitioner need only lightly touch the tip ofthe instrument at an angle to the tooth surface to dislodge the plaque.

[0004] Known ultrasonic scalers, such as scaler 10 illustrated in FIG.1A, have a handpiece 12 a coupled at one end 12 a-1 to a cable 12 bwhich includes a hose, to provide a fluid, and conductors to provideelectrical energy. The other end of the cable 12 b terminates at anelectrical generator and fluid source 12 c. One type of fluid is water.

[0005] The other end of the handpiece 12 a-2 is hollow and is intendedto receive a replaceable insert 14 with a transducer 14 a(magnetostrictive or piezoelectric) carried on the insert. Thetransducer 14 a extends from a proximal end of the insert 14 into thehollow body 12 a-2. An ultrasonically vibrated tip 14 b extends from adistal end of the insert. One such insert has been disclosed and claimedin U.S. Pat. No. 5,775,901, entitled “Insert For Ultrasonic Scaler”,incorporated herein by reference.

[0006] Known magnetostrictive ultrasonic inserts function by exciting astack of thin nickel plates at a frequency equal to the stack's naturalfrequency. The excitation is induced through an electrical generator inunit 12 c, which supplies a current to a coil embedded in the handpiece.When the insert 14 is placed in the handpiece 12 a and the frequencygenerator 12 c is powered on, the operator tunes the generator (manualtuning) until it reaches the resonance frequency i.e., attains thenatural frequency of the insert. Alternately, auto-tune unitsautomatically lock on the insert resonance frequency once powered on. Atthis time, the stack starts vibrating. This vibration of the stack isamplified and transmitted to the tip 12 b by means of a connecting bodyor concentrator. The connecting body is made from material that providesgood sound transmission efficiency.

[0007] While the insert 14 is operational, fluid is pumped through thecable-generator system 12 b, c and through the handpiece 12 a to the tip14 b of the insert 14. The vibrating tip 14 b breaks the fluid streaminto a spray. The spray not only keeps the tip cool, but also keeps thesurface of the tooth cool and provides protection against tissue damage.

[0008] The fluid path through the handpiece 12 a needs to be sealed suchthat no leakage occurs until the fluid stream exits from the insert atthe very tip through a fluid delivery channel. Typically, ultrasonicinserts do not have any moving parts other than the minusculedisplacement of the nickel stack, the connecting body or the tip.

[0009] Known magnetostrictive dental scaling ultrasonic inserts used inthe U.S.A. are designed to vibrate at 25 kHz or 30 kHz frequencies.Another system, popular in Europe, uses a piezoelectric transducer.

[0010] In using an ultrasonic scaler during a cleaning, the dentalpractitioner will need to repeatedly re-orient the location of theinsert tip 14 b with respect to tooth surface depending on which toothof the mouth is being cleaned. In making this angular adjustment, asillustrated in FIG. 1B, the practitioner will typically take the insertout of the patient's mouth, rotate the insert 14, and tip 14 b, insidethe handpiece 12 a locating tip 14 b at a desired angular position. Bothhands are used for this rotation as the frictional forces that produce atight fit of the insert 14 in handpiece 12 a must be overcome. During atypical treatment, the process of reorienting the tip must be carriedout numerous times. This is not only time consuming but also interruptsthe ease and smooth flow of work.

[0011] In areas of the mouth where the practitioner chooses not torotate the insert 14, the practitioner's wrist must be twistedsufficiently to achieve the same function. This twisting action isopposed by the resistance of the cable 12 b, the fluid supply hose andpower conductors, which is attached to the handpiece 12 a.

[0012] There continues to be a need for ultrasonic scalers which aremore comfortable and less fatiguing to use than known instruments.Preferably, any improvements will be downwardly compatible with thenumerous generators and handpieces that are already present in dentaloffices.

SUMMARY OF THE INVENTION

[0013] A rotatable ultrasonic insert has a body section which carries abearing for rotatably engaging an ultrasonic handpiece. The body isrotatable, about an axial centerline.

[0014] Rotation can be effected by applying a force only to the insert.In response, the insert rotates but the handpiece does not. Hence,single handed, two finger rotation is possible.

[0015] Preferably, a swivel feature is located at the gripping region ofthe insert, i.e., close to the treatment tip, where the practitionerwould typically position his or her fingers. The swivel allows theinsert to rotate 360 degrees without any limitation. This enables thepractitioner to position the insert, and the tip, at any angularorientation without having to take the insert out of the patient'smouth. The swivel also allows rotation of the gripping region and tipwithout having to rotate the handpiece and/or the supply cord. Thisremoves the resistance from the operator's hand and reduces handfatigue.

[0016] Additionally, a large diameter grip or handle, not only reducesfinger fatigue but also transmits a larger torque to the swivel featurefor the same amount of force.

[0017] An elastomeric handle, carried by the body, comfortablyinterfaces with a user's fingers. The user can rotate the elastomerichandle and the insert with two fingers relative to the handpiece. Hence,during treatment there will be no need to rotate the handpiece.

[0018] The elastomeric material allows for a positive grip since itdeforms under finger pressure and becomes locally non-cylindrical inshape. The preferred material is silicone. Silicone is not onlyrepeatedly sterilizable under most sterilization processes found indental offices but also provides good traction with respect to the typeof gloves which are commonly used in dental offices.

[0019] The elastomeric handle engages the body only at a region ofminimal ultrasonically induced, vibration. The limited connectivitybetween the body and the elastomeric handle minimizes build up of heatbetween the body and that handle. It also avoids damping ultrasonicvibrations transmitted along the body.

[0020] A method of assembly includes:

[0021] providing a body which carries an ultrasonic transducer, at oneend, and, a displaced treatment applying tip at the other end;

[0022] sliding a rotary handle past the treatment applying tip towardthe bearing;

[0023] connecting the handle to the body at a region of minimalultrasonic vibration.

[0024] In another aspect of the invention, an adaptor has an externalperiphery which can be slidably and releasibly inserted into the openingin the handpiece. A standard ultrasonic insert is inserted through theadaptor into the handpiece. The insert can then be rotated relative tothe handpiece with a rotational force applied only thereto.Alternatively, the adaptor can be snap fitted onto an exterior peripheryof a handpiece.

[0025] Numerous other advantages and features of the present inventionwill become readily apparent from the following detailed description ofthe invention and the embodiments thereof, from the claims and from theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026]FIG. 1A illustrates a prior art ultrasonic scaler having an insertand handpiece;

[0027]FIG. 1B illustrates one aspect of usage of the prior artinsert/handpiece combination of FIG. 1A;

[0028]FIG. 2A illustrates an insert in accordance with the presentinvention;

[0029]FIG. 2B illustrates the insert of FIG. 2A in a handpiece as inFIG. 1A and aspects of usage thereof;

[0030]FIGS. 3A, B and C are various views of an ultrasonic insert bodyin accordance with the present invention;

[0031]FIGS. 4A, B, C and D are various views of a snap-fit rotarybearing usable with the body of FIG. 3A;

[0032]FIGS. 5A, B, C and D are various views of a torque lock inaccordance with the present invention;

[0033]FIGS. 6A, B and C are various views of a swivel housing inaccordance with the present invention;

[0034]FIGS. 7A, B are various views of a cone usable in an insert inaccordance with the present invention;

[0035]FIGS. 8A, B and C illustrate steps in assembling an insert inaccordance with the present invention;

[0036]FIG. 9A is a side sectional view of an insert in accordance withthe invention illustrating the relationship of various elementsassembled in the steps of FIGS. 8A, B and C;

[0037]FIG. 9B is an enlarged sectional view illustrating aspects of asection of FIG. 9A;

[0038]FIG. 10A is a side sectional view of a handpiece carrying asnap-on adaptor in accordance with the present invention;

[0039]FIG. 10B is an enlarged partial side view of the handpiece andadaptor of FIG. 10A with a conventional ultrasonic insert positionedtherein;

[0040]FIG. 10C is an over-all view of an insert as in FIG. 1 combinedwith an adaptor as in FIG. 10A;

[0041]FIG. 11A is an enlarged side view of an alternate embodiment of aninsert in accordance with the present invention;

[0042]FIG. 11B is an enlarged partial side sectional view of the insertof FIG. 11A inserted into a handpiece of an ultrasonic scaling unit,generally of a type illustrated in FIG. 1;

[0043]FIG. 11C is a side view of a portion of the handpiece of FIG. 11B;

[0044]FIG. 11D is a side view of a collar threadable onto the handpieceof FIG. 11B;

[0045]FIGS. 12A, B are top and side views of a preferred form of anultrasonic transducer; and

[0046]FIG. 12C is an end view of the transducer of FIG. 12B.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0047] While this invention is susceptible of embodiment in manydifferent forms, there are shown in the drawing and will be describedherein in detail specific embodiments thereof with the understandingthat the present disclosure is to be considered as an exemplification ofthe principles of the invention and is not intended to limit theinvention to the specific embodiments illustrated.

[0048]FIG. 2A illustrates an insert 20 in accordance with the presentinvention. The insert 20 includes a transducer 20 a which is illustratedas a magnetostrictive transducer. Alternately, it could be apiezoelectric ultrasonic transducer without departing from the spiritand scope of the present invention.

[0049] The transducer is rigidly coupled to an elongated body 20 b whichis covered in part by a cylindrical, elongated deformable elastomericgrip 20 c. The grip 20 c terminates in a cone 20 d which is positionedbetween the grip 20 c and operative treatment applying tip 20 e.

[0050] The insert 20 operates in accordance with the principals of knownultrasonic dental instruments as discussed above relative to FIG. 1A.However, insert 20 also carries a rotary bearing 24 which exhibits ahollow cylindrical stem section 24 a which defines a cylindrical region24 b which receives a sealing O-ring 24 c. The hollow member 24 aterminates at a disc 24 d of larger diameter. A planar surface 24 d-1 ofdisk 24 is adjacent to stem 24 a

[0051] As discussed subsequently, when installed on the elongated body20 b, the rotary bearing member 24 is rotatable relative to the body 20b, gripping member 20 c and tip 20 e. Hence, if the member 24 is fixed,the body 20 b, gripping member 20 c and tip 20 e are readily rotatabletherein.

[0052]FIG. 2B illustrates the standard ultrasonic handpiece 12 a, cable12 b and generator 12 c, discussed above, of a type found in dentaloffices. The insert 20 is slidably receivable, in a direction 16 a, inthe hollow end 12 a-2 of the handpiece 12 a.

[0053] The cylindrical stem 24 a of the rotary bearing 24 slides intothe hollow handpiece 12 a. The O-ring 24 c slidably engages the interiorperiphery of the handpiece 12 a providing a fluid seal and reliablyengaging the insert 20 with the handpiece 12 a

[0054] When installed in the handpiece 12 a, as illustrated in FIG. 2B,insert 20 can be rotated relative to handpiece 12 a with rotary forcesapplied to the deformable gripping member 20 c for purposes of orientingthe tip 20 e relative to a tooth being de-plaqued. As illustrated inFIG. 2B, the practitioner need not restrain the handpiece 12 a whilerotating the insert 20. Additionally, insert 20 is relatively rotatablerelative to handpiece 12 a using only two of the practitioner's fingers.Thus, the orientation of the tip 20 e can be continuously altered withonly two of the practitioner's fingers, requiring only one hand, whilethe scaling operation proceeds. This will reduce operator fatigue andsubstantially shorten the time necessary for the scaling process. Theexpected torque needed to rotate insert 20 preferably will be less than2.0 inch-oz.

[0055] When the practitioner has concluded the de-plaqueing process, theinsert 20 can be removed from the handpiece by pulling it axially fromthe handpiece in a direction 16 b and sterilized. The same insert or adifferent insert can then be subsequently inserted into handpiece 12 ato treat the next patient. It will be understood that the presentinvention is applicable to ultrasonic inserts which utilize eithermagnetostrictive or piezoelectric transducers without limitation.

[0056]FIGS. 3A, 3B, 3C illustrate different views of the body 20 b ofthe insert 20. As illustrated in FIGS. 3A and 3B, body portion 20 b isattached to a first end 20 a-1 of transducer 20 a as would be understoodby those of skill in the art. An elongated cylindrical extension 20 b-1extends axially from transducer 20 a toward tip 20 e.

[0057] The elongated cylindrical metal member 20 b-1, as would be knownto those of skill in the art, is caused to vibrate axially, in responseto electro-magnetic signals received at transducer 20 a from handpiece12 a. The signals are produced by generator 12 c. This axial ultrasonicvibration is in turn coupled to the tip 20 e and used for effectingde-plaqueing of the subject tooth T, in a spray of fluid M, illustratedin phantom in FIG. 3C.

[0058] A pair of notches 20 b-2, 20 b-3 is formed on elongated bodymember 20 b-1 in a region of substantially zero axial ultrasonicvibration. While a pair of notches 20 b-2, -3 has been illustrated inFIG. 3B, it will be understood that a single notch, or three notchescould be used without departing from the spirit and scope of the presentinvention. Additionally, the exact shape of the generally rectangularnotches 20 b-2, -3 is not a limitation of the present invention.

[0059] An interior or base plane 20 b-2′, 20 b-3′ of each notch 20 b-2,-3 is parallel to a plane through the central axis of tip 20 e. Thisnotch/tip configuration facilitates energy transmission along insert 20without increasing the risk of a mechanical fracture due to potentialfatigue stress.

[0060] An elongated fluid flow slot 20 b-4 extends axially in the regionwhere the body 20 b-1 interfaces with the tip 20 e. As discussedsubsequently, fluid for the spray M flows therethrough.

[0061]FIGS. 4A, B, C and D illustrate different views and additionaldetails of rotary bearing 24. As illustrated therein, the cylindricalstem 24 a is hollow and defines an interior peripheral surface 24 ewhich is adjacent to the elongated body portion 20 b, see FIG. 2A. Thebearing member 24 carries a second O-ring 24 c-1 in a cylindrical region24 d-2 which is adjacent to a plurality of radially disposedspring-loaded fingers indicated generally at 24 g.

[0062] The fingers 24 g each terminate at a barbed free end, such as 24g-1, -2, -3 with preferably four such fingers disposed radially aboutthe annular surface 24 d-2. Neither the number nor the exact shape ofthe ends 24 g-1, -2 . . . -n are limitations of the present invention.As discussed in more detail subsequently, the fingers 24 g-1, -2, -3, -4are deflectable radially inward during assembly and are biased radiallyoutwardly to return to their undeflected condition, illustrated in FIGS.4A, 4B.

[0063] The second O-ring 24 c-1 which is positioned adjacent annularsurface 24 d-2 cooperates with O-ring 24 c to provide a sealed fluidflow path between handpiece 12 a and cone 20 d. Cooling fluid flows fromhandpiece 12 a through aperture 24-1, FIG. 4c, and past the fingers 24g-1, -2, -3, -4. It will be understood that the number of fingers 24 gis not a limitation of the present invention.

[0064]FIGS. 5A-5D illustrate various views of a torque lock 30 whichcouples a torque due to force applied to deformable gripping member 20 cby the user's fingers to the body 20 b and treatment tip 20 e. Thetorque lock 30 is preferably molded of a sterilizable thermoplasticwhich, as discussed below, permits it to deform during assembly withoutfracturing.

[0065] The torque lock 30 has a hollow body section 32 a with anexterior periphery 32 b and an internal circumferential periphery 32 c.The torque lock is molded with a slot 34 a formed in the body 32 a whichpermits outward radial deformation of sections 34 b and 34 c, adjacentthe slot 34 a, as the torque lock 30 is slid onto the elongated bodyportion 20 b-1. Surfaces 36 a, 36 b slidably engage the notches 20 b-2,-3 of the elongated member 20 b-1. When the notches are so-engaged, thedeformable members 34 b, c move radially inwardly to a non-deformedcondition. In this state, torque lock 30 is locked to the body 20 b atthe notches 20 b-2, -3.

[0066] The interaction between the surfaces 36 a, b, in the slots 20b-2, -3 inhibits both rotation and translation of the torque lock 30relative to the body member 20 b-1. Hence, rotating the torque lock 30will also rotate the body 20 b of the insert.

[0067] Once the torque lock 30 has been installed on the body member 20b-1 at the slots 20 b-2, -3, it will be fixedly located at a region ofsubstantially zero axial ultrasonic vibration. This minimizes a build-upof heat between the vibrating body 20 b-1 and the torque lock 30. Aswill be understood by those of skill in the art, in addition to locatingthe notches 20 b-2, -3 at a region of minimal axial ultrasonicvibration, preferably centered on the expected nodal point of zerovibration, the cross section of the connecting body portion 20 b-1through the notches 20 b-2, -3 will have a large enough cross-sectionalarea to transmit ultrasonic vibrations without constriction.

[0068]FIGS. 6A, B, C illustrate various views of a housing 40 which ispress fit over torque lock 30 and which slidably and lockingly engagesbarbed fingers 24 g-1, -2, -3, and -4 of the rotary bearing 24. Thehousing 40 has an elongated generally cylindrical body 42 a with asmooth exterior periphery 42 b. The body 42 a terminates at an end 42 cadjacent an annular shoulder 42 d.

[0069] The shoulder 42 d in turn has an end surface 42 d-1. Wheninstalled, the end surface 42 d-1 is adjacent to and rotates relative toannular surface 24 d-3 of bearing 24.

[0070] The annular member 42 d exhibits an internal cylindricalperipheral surface 42 d-2 which traps O-ring 24 c-1 in position, forminga fluid seal with bearing 24 when surface 42 d-1 is positioned adjacentto surface 24 d-3. When so-positioned, the housing 40 can rotaterelative to bearing 24 but is not movable axially relative thereto.

[0071] When the housing 40 is rotated relative to the bearing 24, thesurface 42 d-2 slides over O-ring 24 c-1 without excessive frictionthereby enabling a practitioner to rotate the tip 20 e relative to thehandpiece 12 a with the use of force applied to elastomeric grippingmember 20 c by only two fingers.

[0072] The housing 40 has an interior, cylindrical peripheral surface 42b-1 which surface deflects the barbed fingers 24 g-1, -2, -3, -4radially inwardly when the housing 40 is slid onto the fingers 24 g. Thefingers 24 g, which have been inwardly radially deflected by the surface42 b-1 engage a cylindrical slot 42 b-2 with a snap fit. The radiallycompressed fingers 24 g expand outwardly radially and the barbed ends 24g-1, -2, -3, 4 lock into the slot 42 b-2 precluding axial motion of thehousing 40 away from surface 24 d-3 of bearing 24.

[0073] As the housing 40 is slidably engaging the barbed fingers 24 g-1,-2, -3, -4 and internal cylindrical peripheral surface 42 b-3 engagesexterior cylindrical peripheral surface 32 b of torque lock 30 with apress or interference fit. The press fit between torque lock 30 andhousing 40 locks those two parts together precluding either axial linearmovement or rotary movement therebetween. The end 42 b of housing 40carries a plurality of threads 42 b-4.

[0074] The snap fit between the housing 40 and the rotary bearing 24, incombination with the O-ring 24 c-1 provide a sealed fluid flow path frominflow periphery 24 e of bearing 24 through outflow end surface 42 b-5of housing 40. This fluid flow seal, as noted above, precludes fluidleakage. The exterior cylindrical surface 24 g′ of each of the fingers24 g rotatably engages the internal cylindrical surface 42 b-1 of thehousing 40. This provides a pair of rotatable bearing surfaces whichpermit smooth two finger rotation of the deformable member 20 c and thetreatment tip 20 e. A medically acceptable, sterilizable, lubricant ispreferably provided between the bearing surfaces to improve rotationalsmoothness and further reduce friction and required torque.

[0075]FIGS. 7A and 7B are views of cone 20 d which is carried byrotatable housing 40. Cone 20 d has an internal flow path 50 a which issealed by O-ring 50 b. Cone 20 d includes a set of threads 52. Cone 20 dis coupled to housing 40 by the rotatable engagement of threads 42 b-4of housing 40 and 52 of cone 20 d.

[0076] The O-ring 50 b precludes leakage between an end 50 c and aregion of body portion 20 b-1 which extends therethrough. Fluid exitscone 20 d via fluid flow channel 20 b-4 in the body portion 20 b-1.Fluid exits the cone 20 d in the channel 20 b-4 as a stream. The streamof fluid impacts the vibrating tip 20 e and creates a smooth spraypattern M suited for cooling and cleaning tissues. Adhesives, such asepoxy, can be used to permanently attach the cone 20 d to the housing40.

[0077]FIGS. 8A, 8B and 8C illustrate the steps of assembly of the insert20. Groove 20 b′-1 in body section 20 b′ provides a positive grippingsurface usable during assembly by manufacturing fixtures to block axialmovement of the insert 20.

[0078] As illustrated in FIG. 8A, initial steps of assembly of theinsert 20 include sliding rotary bearing member 24 past operative tip 20e onto body portion 20 b-1. The torque lock 30 is then slid onto theoperative element 20 e and forced along the elongated body 20 b-1, whichin turn forces elements 34 b, c radially outward until surfaces 36 a, bthereof slidably engage the slots 20 b-2, -3. This slidable engagementwith the slots in the body member 20 b locks the torque lock 30 to thebody member 20 b and traps the bearing member 24 against a portion 20 b′of the body 20 b precluding axial movement thereof. The bearing member24 continues to be rotatable relative to the elongated body portion 20b.

[0079] As illustrated in FIG. 8B, the housing 40 is then slid onto andpast the operative element 20 e and forced onto the rotary bearing 24,thereby radially inwardly deflecting the barbefingers 24 g-1, -2, -3, -4and also press fit onto external peripheral surface 32 b of torque lock30 adjacent to disc 24 d. When seated on the bearing member 24, theinwardly deflected fingers 24 g expand into radial slot 42 b-2, axiallylocking the housing 40 to the bearing 24 while still permitting relativerotary motion therebetween.

[0080] The circular elastomeric gripping member 20 c can be slid ontohousing 40 either before or after the cone 20 d is threadably engagedtherewith. The gripping region 20 c has an inner diameter which isslightly smaller than the outer diameter of the housing 40. The member20 c thus elastically attempts to contract around the housing 40 whichminimizes unintended slippage of the grip 20 c relative to the housing40. Member 20 c can also be permanently attached to housing 40 withadhesive.

[0081]FIG. 9A illustrates a side sectional view of an assembled insert20 in accordance with the method of steps of FIGS. 8A, B and C. FIG. 9Bis an enlarged side sectional view of a portion of FIG. 9A furtherillustrating the relationships of the various elements therein.

[0082] As will be understood by those of skill in the art, preferablytip 20 c will be formed and heat treated prior to the start of theassembly process illustrated in FIG. 8A. By forming housing 40 as aseparate element from core 20 d, the length of each is less than thecombined length of 20 d and 40. Hence, each can be independently slidover exemplary curved tip 20 e though the assembled combination 20 d and40 will not slide over tip 20 e.

[0083]FIG. 10A illustrates a snap-on plastic adaptor 70 which isintended to be used with a standard handpiece, such as the handpiece 12a. As illustrated in FIG. 10A, handpiece 12 a includes an annulardepression 12 c adjacent to open end 12 a-2. The adaptor 70 snap-fitsonto the handpiece 12 a at the groove 12 c.

[0084] Adaptor 70 has a body section 72 a which carries an annularlocking protrusion 72 b which slidably engages the slot 12 c locking theadaptor 70 thereto. The adaptor 70 also includes a bearing 74 a which iscarried in an interior region 74 b of the body 72 a. An O-ring seal 74 ccan be positioned adjacent to the bearing 74 a to minimize thelikelihood of leakage from fluid flowing through the handpiece 12 a intoan insert coupled thereto.

[0085] The insert 70 defines a channel 76 a which co-extends with andabuts channel 12 d in handpiece 12 a. The channels 76 a and 12 d receivea standard insert such as the insert 14, which is to be rotatablycoupled to handpiece 12 a and to be energized thereby.

[0086]FIG. 10B illustrates added details of standard insert 14 coupledto adaptor 70 for rotation relative to handpiece 12 a. In the embodimentillustrated in FIG. 10B, the adaptor 70 in combination with handpiece 12a and insert 14 provide a sealed fluid flow path between the interiorperipheral surface 12 b of the handpiece and tip 14 b of the insert. Inthis configuration, a user can rotate insert 14 relative to handpiece 12a by applying rotary forces to the grip 14 c in a manner analogous tothe way in which rotary forces are applied to the grip 20 c of rotatableinsert 20 previously described.

[0087] Using insert 70, a standard handpiece, in combination withstandard inserts, such as the insert 14, can cost effectively provideimproved convenience and comfort for the practitioner. It will beunderstood, if desired, that the insert 70 could be color coded. Theinsert 70 can be molded of any sterilizable plastic such a thermoplasticmaterial commercially available and known as polyphenylsulfone. It willalso be understood that a plurality of snap-fit fingers, such as thefingers 72 b, can be molded in housing 72 a for purposes of releasiblyattaching the adaptor to the handpiece 12 a.

[0088]FIG. 10C is an over-all view of insert 14 coupled to handpiece 12a via adaptor 70.

[0089]FIGS. 11A and 11B illustrate an alternate form of an adaptor 80usable with a handpiece 82. The adaptor 80 includes a cylindrical bodysection 80 a which carries a bearing 80 b which could be implemented asa plastic ring bearing. The bearing 80 b is carried in a cylindricalslot 80 c in housing 80 a.

[0090] Housing 80 a also carries an O-ring seal 80 d in a second slot 80e. Finally, the body 80 a terminates at a plurality of deflectablelocking fingers 80 f. The body 80 a is hollow and defines an internalperipheral cylindrical surface 80 g.

[0091] Insert 80 is slidably receivable into handpiece 82 with asnap-fit. The exterior surfaces of the fingers 80 f slidably engage alocking slot 82 a formed in an interior peripheral surface 82 b of thehandpiece 82. The interior peripheral surface 82 b also includes a slot82 c for receipt of the O-ring seal 80 e, and, a slot 82 d whichreceives the rotary bearing 80 b carried by the insert 80. It will beunderstood that the O-ring 80 d provides a fluid seal between handpiece82 and an insert, such as the insert 14 shown in part in phantom, whichhas been slidably inserted into the adaptor 80 in contact with theinternal peripheral cylindrical surface 80 g. When so-inserted, theinsert 14 can be rotated, along with adaptor 80 relative to thehandpiece 82 so as to promote the convenience and comfort of apractitioner. A collar 86 is threadable onto the end of the handpiece 82to trap the adaptor 80 in place and prevent axial movement thereof.

[0092] FIGS. 12A-C illustrate details of a preferred structure of stack20 a. By impressing a “W” bend 20 a-1 along the length of each member ofthe stack, as illustrated, stiffness of the stack can be increased. Thisin turn promotes continued alignment of the stack relative to centralaxis HP-A, see FIG. 2B, while the insert 20 is being rotated. Theimproved alignment minimizes the likelihood of the stack 20 a rubbingagainst internal peripheral surface 12 d during rotation, henceeliminating a possible source of friction and noise.

[0093] From the foregoing, it will be observed that numerous variationsand modifications may be effected without departing from the spirit andscope of the invention. It is to be understood that no limitation withrespect to the specific apparatus illustrated herein is intended orshould be inferred. It is, of course, intended to cover by the appendedclaims all such modifications as fall within the scope of the claims.

1-69. (canceled)
 70. An ultrasonic insert which is engageable with ahollow handpiece, the insert comprising: a treatment applying tip; anultrasonic transducer coupled to the tip; and a rotary bearingnon-removably carried between the transducer and the tip wherein thebearing is rotatable relative to the tip.
 71. An insert as in claim 70wherein the bearing comprises a cylindrical sleeve rotatably carriedadjacent to the end of the transducer.
 72. An insert as in claim 70which includes a generally cylindrical, manually grippable sectionbetween the tip and the bearing wherein the bearing is rotatablerelative to the grippable section.
 73. An insert as in claim 70 whereinthe bearing comprises a cylindrical sleeve rotatably carried adjacent toan end of the transducer, and wherein the sleeve rotatably abuts an endof a grippable element.
 74. An insert as in claim 73 wherein the sleeveincludes an exterior feature slidably engageable with the handpiece. 75.An insert as in claim 73 wherein the sleeve carries an annular flange ofgreater diameter than the sleeve wherein the flange rotates adjacent tothe grippable element.
 76. A rotatable ultrasonic dental insertcomprising; a treatment applying tip, a transducer non-rotatably coupledto the tip and a handpiece engaging element, rotatably coupled to thetip, wherein the tip is rotatable relative to the engaging element by aforce applied adjacent to the tip.